Albert j



A. J. CROLL.

FIELD MAGNET.

APPLICATION FILED JULY 26, 191B.

'1 ,3 1 4, 1 28. Patented Aug. 26, 1919.

ALBERT J. GROLL, OF ROCHESTER,

COMPANY, OF ROCHESTER,

NEW YORK, ASSIGNOR TO NEW YORK, A CORPORATION OF N EW YORK.

NORTH EAST ELECTRIC FIELD-MAGNET.

Specification of Letters Patent.

Patented Aug. 26, 1919..

Application filed July 26, 1918. Serial No. 246,980.

To (172 whom it may concern:

Be it known that I, ALBERT J. Grow, a citizen of the United States, residing at Rochester, in the county of Monroe and State of New York, have invented certain new and useful Improvements in Field- Magnets; and I do hereby declare the f ollowing to be a full, clear, and exact description of the invention such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to a field-magnet for use in electric motors or generators, or other apparatus.

In dynamo-electric machines of the ironclad type, in which the field-poles are in the form of inward projections from a ring or shell of iron, it is common to-use wind-,

ings, upon the polar projections, ing forn1-wound coils which are placed, already wound, on the projections. To combine magnetic eiiiciency with economy of material, the polar projections should have comparatively slender necks and wide faces, but this form introduces difiiculty in applying the coils to the projections, unless the projections are made separable, in whole or in part, from the ring or shell of the field magnet. I

The object of the present invention is to produce a field-magnet, of the type in question, in which the polar projections are integral with thebody-members by which they are magnetically connected, but in which the coils may be easily applied to and removed from the necks of the polar projections.

To the foregoing end the invention resides in a field-magnet made up of several members, equal in number to the polar projections. Each member consistsof one or more sections, according as it is of solid or laminated construction, and these sections have a form characteristic of the invention. Each section comprises a neclrportion, adapted to receive a coil, and horns projecting from the inner'end of the neclr so as to provide a wide polar face. From one side only of the neck, at its outer end, projects abody-member which is formed to on a the neck-portion tend into engagement wit" of the next adjacent polar projection, thus connecting the projections magnetically. The body-portion is of a width no greater than that of the neck, and is preferably comprisunited to the latter by a smooth curve, so that the coil may be passed oVer the body portion lengthwise and swung into position. upon the neck. I

Other features of the invention will be pointed out in connection with the following. description of the illustrated embodiment thereof.

In the accompanying drawings Figure 1 is a side-elevationof a field-magnet embodying the present invention, with one of the coils shown in section. Fig. 2 is a side-elevation of one member of the magnet, showing the manner in which he coil is applied. Fig. 3 is a side-elevation showing the mannor in which the parts are assembled in constructing the magnet in a modified form, and F igs. 4 and 5 are detail-views in side-elevation and plan, respectively, of such modified form. Fig. 6 is a side-elevation, partly in vertical section, of an embodiment of the invention in a four-pole field-magnet.

In Figs. 1 and 2 the invention is shown as embodied in a field-magnet of laminated. construction, with two poles. The magnet comprises two core-members, each made up of any convenient number of similar laminae or sections. Each section comprises a neck 19, from which horns 11 extend in opposite d1rections, thus producing a polar projection of conventional form.

From one side ofthe neck 10 a bodyportion 12 extends, being united with the neck by smooth curves. Each body-portion has an extremity 13 which is concave so as to fit closely against the convex surface 14 of the neck of an adjacent polar projection. Oonsequently, the body-portions constitute magnetic connections or okes between the pr0- jections or poles. he several laminae of each member are shown as secured together by rivets 16, while the two members so constituted may be held in the relative position shown in Fig. 1 by any convenient means.

The construction just described has two important and correlative advantages" the sections may be inexpensively formed by punchings of sheet-metal, and coils already formed and taped may be easily put in place on the necks or" the polar pro ections. The manner in which thecoils are so placed is clearly illustrated in Fig. 2.

In the construction shown in Fig. 1 the members must be held in cooperative relation by extraneous means. To gain greater Til inc

mechanical strength, and to reduce the magnetic reluctance of the joints between the members, it may be desirable to arrange the laminae of adjacent members in overlapping relation. This ma be done, without any alteration of the s ape of the sections, as shown in Figs. 3, 4 and 5. In this case the alternate sections formin each polar projection are arranged wit their body-portions extending in opposite direction, so that they overlap and alternate with the bodyportions of the sections forming the opposite polar projection. The rivets 16 then act to secure. all of the sections rigidly together, in a unitary core-structure.

In using the sections as -j ust described it is necessary to ap ly the coils before the sections are rivete together.

introducing the body-portions of the sections into each coil two at a time and from opposite sides, as shown in Fig. 3. After the sections forming each polar projection have thus been brought to their roper relative position, with the coil encirc 1ng their neckportions, the assembly so formed may be properly correlated wlth another similar assem ly, by interposing the re ective bodyortions,,and the rivets may t en, be introuced.

By changing the extent of the body-por-.

tions the construction characteristic of the resent invention may be apfilied to the ormation of multipolar as we as bi-polar magnets. Fig. 6 shows a -pole magnet so This is done by formed. In this case the members are shown as each comprising only a single solid section, though the laminated structures of Figs. 1 and 4 may be used with equal facility.

As a convenient means for securing the members or sections together, when the con struction of Fig. 4 is not used, the members may be closely embraced in and supported by an inclosing shell or ring 17, of magnetic or non-magnetic material.

While the illustrated sections are all shaped to produce a magnet of a generally circular form, this is not an essential feature of the invention, and the invention is not, in general, limited to the details of construction of the illustrated embodiments thereof.

The invention claimed is:

1. A field-magnet consisting of a plurality of sections, each section comprising a nec adapted to receive a coil; horns projectin from the inner end of the neck; an elongated body-portion extending, from one side only of the neck, into enga ement with the neck of another section; an coils on the necks.

2. A field-magnet, as in claim 1, in which said. sections are in the form of laminae superposed in their body-' ortions extending alternately in opposite directions from the neck-portion so as to interlock with the body-portions oi the sections constituting the next adjacent pole or poles.

. ALBERT J. CROLL.

the neckportion and with 

